Ruthenium complexes useful as carriers for immunologically active materials

Abstract

The invention relates to a ruthenium complex having the formula Ru2+L1L2L3I wherein L1, L2 and L3 are the same or different are equal to a bi- or polycyclic ligand with at least two nitrogen-containing heterocycles, whereby at least one of these ligands is substituted with at least one group conferring water-solubility, and whereby at least one of these ligands is substituted, optionally via a spacer group, with at least one reactive group, and whereby the ligands L1, L2 and L3 are attached to the ruthenium via nitrogen atoms. The invention is further related to such ruthenium complexes having coupled thereto an immunologically active material, for example, antigens, haptens or antibodies and to the use of said ruthenium complexes in fluorescence spectroscopy. Specific ligands L1, L2 and L3 which are useful in the ruthenium complexes of the invention are, e.g., 2,2'-bipyridine, 1,10-phenanthroline benzbathophenanthroline or bathophenanthroline groups. Groups which are useful for conferring water-solubility on said ligand are, e.g. sulfonic acid groups which are preferably present in the form of their salts. Useful spacer groups are e.g. an alkylene groupcontaining 1-8 carbon atoms and which is optionally substituted with -SO2-NH-, -S-, -O-, -COO- or -CO-NH- groups. Useful reactive groups to which the immunologically active material is coupled, are e.g. -COOH, -I, -NH2, -NCS or -SO2Hal groups. The ruthenium complexes according to the present invention can be detected with great sensitivity by fluorescence spectroscopy and are thus useful in fluorescense immunoassays.

What is claimed is: 
     
       1. Ruthenium complexes to which are coupled an immunologically active material, whereby the ruthenium complexes have the general formula   R.sup.2+ L.sub.1 L.sub.2 L.sub.3                           I     wherein L 1  and L 2  are the same or different and are bathophenanthroline or benzobathphenanthroline groups substituted with sulphonic acid groups as groups conferring water-solubility, and wherein L 3  is a member of the group consisting of a bathophenanthroline group and a benzobathophenanthroline group, both of which are substituted with an alkylene group having a maximum of eight carbon atoms which is terminally substituted with a --COOH, --NH 2  --NCS, --I or --SO 2  Hal group.   
     
     
       2. A ruthenium complex according to claim 1, wherein the alkylene of the ligand L 3  contains --SO 2  --NH--, --S--, --O--, --COO-- or --CO--NH-- groups. 
     
     
       3. A ruthenium complex according to claim 1, wherein the ligand L 3  is substituted with the group --SO 2  --NH--(CH 2 ) n  COOH in which n is a whole number of from 1-5. 
     
     
       4. A ruthenium complex according to claim 1, wherein the ligand L 3  is substituted with the group --(CH 2 ) 4  --COOH. 
     
     
       5. A ruthenium complex according to claim 1, wherein the ligand L 3  is substituted with the group --(CH 2 ) 5  --COOH. 
     
     
       6. A ruthenium complex according to claim 1, wherein the immunologically active material is an antigen or hapten. 
     
     
       7. A ruthenium complex according to claim 1, wherein the immunologically active material is an antibody. 
     
     
       8. A ruthenium complex according to claim 7, wherein the immunologically active material is an antibody against carcinoembryonal antigen, human choriongonadotropin or α-interferon.